EP3482661B1 - Method for adapting a heating output of at least one heating element of a domestic appliance - Google Patents

Description

The present invention relates to a method for adapting a heating power of at least one heating element of a domestic appliance. The invention also relates to a system, a domestic appliance and a computer program product.

It is known from the prior art that, in household appliances and in particular in kitchen appliances, food is heated while the food is being prepared manually or by the household appliance. For example, during operation of an agitator, e.g. B. during a stirring process for a soup or the like, the heating take place. In this case, a target temperature is usually specified by a user of the domestic appliance, to which the medium in the receiving space, in particular a stirred vessel, is to be heated. A heating control can be used for this a heating element of the domestic appliance can be carried out, which uses a measured temperature, for example. In the stirred vessel as a control variable. For example, an electrical temperature sensor, such as a temperature-dependent resistor, is used to record the temperature EP2388564A1 discloses a household appliance with heating power adjustment.

A major technical challenge in such applications is that such a temperature sensor can only measure a local temperature that deviates from the actual temperature of the medium. For example, the temperature sensor is integrated in a (mixing vessel) base and is therefore not in direct contact with the medium (in the mixing vessel), i.e. the prepared food. Another difficulty lies in the fact that the heat in the space where the food is received or in the mixing vessel may not be evenly distributed, especially if a motor of an agitator in the mixing vessel does not rotate or only rotates slowly or the level of the food in the mixing vessel is too high. In principle, there is therefore a problem that the temperature measured (especially in the case of a stirred vessel), which is used to regulate the heating of the domestic appliance, especially the kitchen appliance, deviates from the actual temperature of a medium in the receiving space or in the stirred vessel. Another problem is that the medium is only heated unreliably and slowly on the basis of the measured temperature.

It is therefore an object of the present invention to at least partially remedy the disadvantages described above. In particular, it is the object of the present invention to propose an improved adaptation of a heating output of a domestic appliance, and in particular of a kitchen appliance.

The above object is achieved by a method with the features of the independent method claim, by a system with the features of the independent system claim, by a domestic appliance with the features of the independent device claim and by a computer program product with the features of the further independent device claim. Further features and details of the invention emerge from the respective subclaims, the description and the drawings. Features and details that are described in connection with the method according to the invention naturally also apply in connection with the system according to the invention, the Household appliance according to the invention and the computer program product according to the invention, and vice versa, so that with regard to the disclosure, reference is or can always be made to the individual aspects of the invention.

The object is achieved by a method for adapting a heating power of at least one heating element, for. B. a resistance heater or a thick-film heater or an induction coil or the like, of a domestic appliance, in particular a kitchen appliance, wherein the adjustment of the heating power for heating control is preferably carried out. The heating power of the heating element can be adjusted by, for example, regulating an electrical energy supply to the heating element. In this way, heating of the heating element or by means of the heating element can be brought about in order to heat a medium in a receiving space of the domestic appliance, in particular in a mixing vessel of the kitchen appliance. The medium includes z. B. at least one food in the receiving space (z. B. in a pot of the food processor).

In particular, it is provided that the household appliance, in particular the kitchen appliance, is designed for the at least partially automatic preparation of food, for example by a receiving space, in particular a mixing vessel or an oven, for receiving the food and / or by a stirrer for stirring the food and / or by the heating element for heating the food.

Furthermore, the domestic appliance, in particular the kitchen appliance, can have a temperature sensor for measuring a temperature in the receiving space, in particular the mixing vessel of the kitchen appliance. The temperature sensor and / or the heating element are, for example, integrated in a floor for the receiving space, in particular the floor of the mixing vessel or a stove top or an oven floor, wherein the temperature sensor can optionally also be integrated in the heating element. For example, a control device can be provided for automatic preparation, which controls the agitator and / or the heating element on the basis of a predetermined recipe or a user input.

• a) Durchführen einer Aufheizphase mit einer derartigen Heizleistungsanpassung (des Heizelements), dass die (gemessene) Temperatur (insbesondere als Ist-Temperatur) eine vorgegebene Soll-Temperatur anstrebt, insbesondere durch eine Heizregelung, wobei vorzugsweise die Temperatur regelmäßig und/oder zyklisch durch den Temperatursensor gemessen wird,
• b) Durchführen einer Temperaturhaltungsphase, wenn die (lst-) Temperatur die Soll-Temperatur erreicht hat, wobei in der Temperaturhaltungsphase eine Heizleistungsbegrenzung erfolgt,
• c) Durchführen wenigstens einer Auswertung der (lst-) Temperatur anhand der Soll-Temperatur während der Temperaturhaltungsphase, sodass ein Auswertungsergebnis bestimmt wird,
• d) Durchführen einer Stabilisierungsphase, wenn das Auswertungsergebnis ein Stabilisierungskriterium erfüllt, wobei vorzugsweise in der Stabilisierungsphase die Heizleistungsanpassung derart erfolgt, dass die (lst-) Temperatur eine bestimmte Stabilisierungstemperatur anstrebt, wobei die Stabilisierungstemperatur größer ist als die Soll-Temperatur.

In the process Z according to the invention, the following steps are carried out:

• a) Carrying out a heating phase with such a heating power adjustment (of the heating element) that the (measured) temperature (in particular as the actual temperature) aims at a predetermined target temperature, in particular by means of a heating control, with the temperature preferably being controlled regularly and / or cyclically by the Temperature sensor is measured,
• b) Carrying out a temperature maintenance phase when the (actual) temperature has reached the target temperature, with heating output being limited in the temperature maintenance phase,
• c) performing at least one evaluation of the (actual) temperature based on the target temperature during the temperature maintenance phase, so that an evaluation result is determined,
• d) Carrying out a stabilization phase when the evaluation result fulfills a stabilization criterion, with the heating output being preferably adjusted in the stabilization phase in such a way that the (actual) temperature strives for a certain stabilization temperature, the stabilization temperature being greater than the target temperature.

In other words, the stabilization temperature can be a new setpoint temperature which has a higher temperature value than the originally specified setpoint temperature. In this way, a kind of override of the heating power adjustment or heating control can take place. This has the advantage that the medium temperature can reach the desired temperature value more quickly through a simple and inexpensive adaptation of the heating power adaptation or heating control. For this purpose, a temperature- and / or time-dependent stability criterion can be established, which, for example, is determined empirically and / or is specified by a user. Particularly advantageous examples of such a stability criterion are also discussed below.

It is also possible for the method according to the invention and / or the steps of the method to be carried out iteratively, in particular during the preparation of a foodstuff, in order to optimize the preparation.

In particular, steps b), c) and d) are carried out iteratively, preferably until the stabilization criterion is no longer met. If the stabilization criterion is no longer met (that is to say, in particular, the evaluation result no longer fulfills the stabilization criterion), a temperature maintenance phase can then possibly be carried out (again) in accordance with a further step e). A concrete example for the stabilization criterion is explained in more detail below.

The home appliance can, for. B. be designed as a kitchen appliance and / or as a household appliance and / or as a kitchen appliance and / or as an oven and / or as a stove and / or the like, and preferably have a receiving space in which food is prepared manually or automatically . For this purpose, the food z. B. be positioned on a floor of the receiving space. As a heating element, z. B. also an electrical device, e.g. B. a heating plate, possibly also for the use of induction heating. The receiving space can accordingly also be an oven space, cooking space or a stove top or a stirring vessel or the like.

It can be particularly advantageous that the method according to the invention is understood as an intelligent method which is used for the preparation, in particular for cooking, of food by the domestic appliance, in particular the kitchen appliance. For this purpose, a difference between a measured temperature and the medium temperature can be determined and / or the food can be quickly heated to the target temperature by an iterative process. In particular, the medium is understood to mean the at least one food in the receiving space, in particular in the stirred vessel.

It is conceivable that during cooking (in particular with a low motor speed of a stirrer in a mixing vessel of a food processor and / or with a high filling quantity of a medium in the mixing vessel) a large temperature difference occurs between a measured temperature and an actual temperature of the medium. This is e.g. For example, the reason is that a temperature sensor, especially an NTC sensor (i.e. an NTC thermistor), cannot measure directly in the medium for structural reasons, but is only located close to the medium (e.g. in a floor of the mixing vessel). Another reason can be that the heat is only slowly transferred to the entire medium. Conventionally, the heating control is carried out in such a way that the heating with the heating element is only controlled against the target temperature. As a result, the difference is retained for a long time, so the convergence takes place only slowly.

In particular, it was found that this approach accelerates when the target temperature is briefly increased. For example, three phases can therefore be used to perform an improved heating adjustment: a heating-up (i.e. a heating-up phase), a stabilization (i.e. a stabilizing phase) and a temperature holding (i.e. a temperature holding phase). At least one parameter can be defined for each of these heating phases, i. H. these phases can be parameterized. For example, for temperature maintenance phase B, a power limit can be defined to limit the heating power (e.g. with 40% or 80% of the highest power, i.e. a maximum power).

Provision can be made for the heating phase to be carried out first for each cooking process (that is to say for each preparation) in the domestic appliance, in particular the kitchen appliance. In this case, the heating output can be adjusted, in particular heating regulation, in such a way that the measured temperature reaches the setpoint temperature as quickly as possible. When the measured temperature has reached the target temperature, the heating output adjustment can switch to the temperature maintenance phase. The heating can be controlled with a limited maximum output (e.g. a maximum of 40% or a maximum of 80%) in accordance with the heating output limitation. Then the temperature is further measured, e.g. B. the lowest measured temperature is stored, and if a difference between the lowest temperature and the target temperature (z. B. the target temperature) exceeds a threshold value, then the heating output adjustment changes to the stabilization phase. A new target temperature (stabilization temperature) can be set for the stabilization phase.

It is then conceivable that the heating output adjustment in the stabilization phase regulates the heating output against this new setpoint temperature and, if necessary, a timer runs at the same time. If, based on the timer, a period of time is exceeded, in particular Stabilization time, is detected, the heating output adjustment can switch back to the temperature maintenance phase. It is also possible to switch to the temperature maintenance phase if the measured temperature exceeds the new target temperature and / or the stabilization criterion is no longer met. These phase changes can occur automatically several times if necessary.

In particular, it can be possible for the heating phase to start again when a target temperature is set again (for example by a user) to a different value. The heating-up phase can also start again when a lowest measured temperature is below the setpoint temperature by a predefined distance.

It can be advantageous if, within the scope of the invention, the stabilization temperature is determined on the basis of the evaluation result, the stabilization temperature preferably being limited by a maximum offset. In other words, the stabilization temperature can be variable and, for example, depending on the setpoint temperature and / or on the measured temperature. It can also be possible for a slope of a curve of measured temperature values of the measured temperature to be used to determine the stabilization temperature. By using a maximum offset as a maximum value for the stabilization temperature, the stability of the method according to the invention can also be increased.

It is also optionally conceivable for the heating output to be adjusted in order to limit the heating output in such a way that the heating output is limited to a predetermined maximum holding heating output, with the heating output being adjusted during the heating-up phase and / or the stabilization phase, in particular as a heating output control, in such a way that the heating output limitation is canceled, and, in particular, the heating output can correspond at most to the maximum heating output, and / or during the stabilization phase the heating output is adjusted in such a way that the heating output limitation is limited to a higher value than during the temperature maintenance phase / or the stabilization phase is limited to another limit value. It can be decisive here that the heating output in the temperature maintenance phase is always lower than in the heating phase and / or the stabilization phase. This enables an efficient and rapid homogenization of the temperature in the medium.

Furthermore, it can be provided within the scope of the invention that, when limiting the heating output, in particular for the temperature maintenance phase, the heating output is set to a predetermined maximum heating output in the range of 10% to 90%, preferably 20% to 70%, preferably 30% to 60%, particularly preferred 40% to 50%, in particular 35%, of a maximum heating power is limited. For example, the maximum heating output is such a heating output that can be provided at a maximum by the heating control of the domestic appliance, in particular the kitchen appliance.

Provision can preferably be made for one or more temperature values to be determined by at least one measurement of the temperature during the temperature maintenance phase for temperature monitoring, the evaluation being carried out in step c) in that a difference in the determined temperature value or one of the determined temperature values, in particular a minimum of the Temperature values, and the target temperature is determined, the difference preferably forming the evaluation result. It can also be possible that the comparison of the difference with a threshold value, which can be predefined, for example, forms the evaluation result. It is also advantageous if the minimum of the temperature values is determined from at least two or at least five or at least ten or at least 100 or at least 120 temperature values. This enables the stabilization phase to be carried out reliably.

The operation of forming a minimum mentioned in the context of this invention can, for example, be determined on the basis of all temperature values which were determined in a corresponding phase (in which the minimum is formed).

• Durchführen eines Wechsels von der Stabilisierungsphase in die Temperaturhaltungsphase, wenn die ermittelte zeitliche Stabilisierungsdauer eine bestimmte Stabilisierungszeitvorgabe übersteigt.

Advantageously, it can be provided within the scope of the invention that, during the stabilization phase, a temporal stabilization duration for carrying out the stabilization phase is determined, the following step being provided after step d):

• Carrying out a change from the stabilization phase to the temperature maintenance phase if the determined stabilization duration exceeds a certain stabilization time specification.

For example, the temporal stabilization duration can be determined using a timer (e.g. a corresponding electronic module for time determination). The preset stabilization time can optionally also be stored in advance, e.g. in an electronic storage unit. Both the memory unit and the timer can be integrated in a processing device, e.g. a microcontroller and / or an integrated circuit and / or electronics of the household appliance or the kitchen appliance.

• Durchführen eines Wechsels von der Stabilisierungsphase in die Temperaturhaltungsphase, wenn während der Stabilisierungsphase eine Bewertung des Temperaturwertes anhand der Stabilisierungstemperatur ein Abbruchkriterium erfüllt, insbesondere wenn durch den Temperaturwert indiziert wird, dass die Temperatur die Stabilisierungstemperatur erreicht hat.

Another advantage can be achieved within the scope of the invention if at least one temperature value is determined by at least one measurement of the temperature during the stabilization phase for temperature monitoring, the following step being provided after step d):

• Carrying out a change from the stabilization phase to the temperature maintenance phase if, during the stabilization phase, an assessment of the temperature value based on the stabilization temperature fulfills a termination criterion, in particular if the temperature value indicates that the temperature has reached the stabilization temperature.

In other words, it can be provided that either a stabilization time specification is reached as the maximum duration, in particular stabilization time, for carrying out the stabilization phase or the measured temperature reaches the stabilization temperature so that the stabilization phase is aborted and a change to the temperature maintenance phase takes place.

Advantageously, the invention can provide that during the heating-up phase for temperature monitoring several temperature values are determined by measuring the temperature, so that a temperature increase (ie in particular a long-term increase in a temperature curve which is determined from the temperature values) is determined a relationship between the evaluation result determined in accordance with step c) and the ascertained temperature rise is determined, the stabilization time setting preferably being limited by a maximum duration which is preferably in the range from 100 s to 1000 s, preferably 200 s to 800 s. The stability of the method according to the invention can thus be increased.

• Durchführen eines Wechsels von der Stabilisierungsphase in die Aufheizphase, wenn während der Stabilisierungsphase eine Bewertung des Temperaturwertes ein Aufheizkriterium erfüllt, insbesondere wenn eine Temperaturdifferenz zwischen dem Temperaturwert und der Soll-Temperatur einen vorgegebenen Schwellenwert (z. B. Threshold_aufh) überschreitet.

Furthermore, it can be provided within the scope of the invention that during the stabilization phase for temperature monitoring at least one temperature value is determined by at least one measurement of the temperature, the following step after step d) being provided:

• Carrying out a change from the stabilization phase to the heating phase if an evaluation of the temperature value fulfills a heating criterion during the stabilization phase, in particular if a temperature difference between the temperature value and the target temperature exceeds a predetermined threshold value (e.g. Threshold_aufh).

The temperature value for forming the temperature difference can also be the minimum temperature value from a series of different temperature values. In this way, the heating of the medium can be further improved.

Furthermore, it can be provided that during the heating phase and / or during the temperature maintenance phase and / or during the stabilization phase, temperature monitoring is carried out in that several measurements of the temperature are carried out one after the other, preferably at regular intervals, by the temperature sensor, in each case at least to determine a temperature value in order to carry out the evaluation according to step c) in particular on the basis of the temperature value and / or to determine when the temperature has reached the target temperature and / or the stabilization temperature. As described above, a minimum can advantageously also be formed from a plurality of temperature values, so that the lowest (minimum) temperature value is used to form a difference.

Furthermore, it is optionally provided that the heating phase and / or the temperature maintenance phase and / or the stabilization phase is carried out during the preparation of a food in order to heat the food in the receiving space, in particular in the stirred vessel, to the target temperature, the measured temperature for the temperature of the food is specific and deviates from this, whereby preferably the stabilization temperature and / or stabilization period (i.e. a time duration with which the stabilization phase is carried out) is determined in such a way that in the stabilization phase the temperature of the food is brought into line with the target temperature at a higher rate than in the temperature maintenance phase. For this purpose, the stabilization temperature is advantageously selected to be greater than the predefined setpoint temperature. For example, the stabilization temperature is selected to be at least 1 K, or at least 2 K, or at least 5 K, or at least 10 K, or a maximum of 20 K higher than the specified target temperature. This enables the medium to be heated effectively.

Furthermore, it can be provided within the scope of the invention that the stabilization criterion, in particular during step b) and / or during the temperature maintenance phase, is fulfilled when the evaluation result, preferably a difference between a determined temperature value or one of the determined temperature values, in particular a minimum of the temperature values , and the target temperature exceeds a predefined threshold value (e.g. Threshold_stb), the threshold value preferably being set independently of the food, and preferably the threshold value in the range from 1 K to 10 K, preferably 2 K to 9 K, preferably 3 K. up to 8 K, particularly preferably 3.8 K to 7 K, preferably exactly 3.8 K. By using a food-independent threshold value, the advantage can be achieved that the method according to the invention can be carried out in the same way for different foodstuffs and thus simply and inexpensively.

The stabilization criterion can advantageously (in particular only) be met when the evaluation result exceeds a predefined threshold value (e.g. Threshold_stb). The evaluation result is z. B. formed in that a difference or an amount of a difference between a determined temperature value or one of the determined temperature values, in particular a minimum of the temperature values, and the target temperature is formed. In other words, the stabilization criterion can be met when the distance between the actual temperature and the target temperature becomes too great.

Optionally, it can be provided that the stabilization temperature is an offset greater than the target temperature, the offset being the difference between the target temperature and at least one temperature value determined in the temperature maintenance phase, in particular a minimum of these temperature values, is determined, and in particular a maximum offset in the range from 8 K to 20 K, preferably 10 K to 15 K, preferably 12 K to 14 K, in particular at least 5 K , particularly preferably can correspond to a maximum of 20 K. A particularly effective heating of the medium is thus possible.

• wenigstens einen Temperatursensor zur Durchführung wenigstens einer Messung einer Temperatur bei einem Aufnahmeraum des Hausgeräts, insbesondere bei einem Rührgefäß der Küchenmaschine,
• wenigstens eine Ansteuerungsvorrichtung zur Ansteuerung wenigstens eines Heizelements des Hausgeräts, insbesondere der Küchenmaschine, in Abhängigkeit von einer Heizleistungsanpassung, sodass in einer Aufheizphase die Temperatur eine vorgegebene Soll-Temperatur anstrebt, und in einer Temperaturhaltungsphase eine Heizleistungsbegrenzung erfolgt,
• wenigstens eine Verarbeitungsvorrichtung zur Auswertung der Temperatur anhand der Soll-Temperatur zumindest in der Temperaturhaltungsphase, wobei vorzugsweise die Verarbeitungsvorrichtung dazu ausgeführt ist, eine Stabilisierungsphase in Abhängigkeit von der Auswertung zu initiieren, wobei in der Stabilisierungsphase die Heizleistungsanpassung derart durchführbar ist, dass die Temperatur eine bestimmte Stabilisierungstemperatur anstrebt, wobei die Stabilisierungstemperatur größer ist als die (vorgegebene) Soll-Temperatur.

The invention also relates to a system for adapting a heating power in a household appliance, in particular in a kitchen appliance, having:

• at least one temperature sensor for carrying out at least one measurement of a temperature in a receiving space of the domestic appliance, in particular in a mixing vessel of the food processor,
• at least one control device for controlling at least one heating element of the household appliance, in particular the kitchen appliance, depending on a heating output adjustment, so that the temperature strives for a predetermined target temperature in a heating phase, and heating output is limited in a temperature maintenance phase,
• at least one processing device for evaluating the temperature on the basis of the target temperature at least in the temperature maintenance phase, the processing device preferably being designed to initiate a stabilization phase as a function of the evaluation Aims at stabilization temperature, the stabilization temperature being greater than the (predetermined) target temperature.

The system according to the invention thus has the same advantages as have been described in detail with reference to a method according to the invention. In addition, a system according to the invention can be designed to be operable by a method according to the invention.

It is also conceivable that the heating element is integrated in the receiving space, in particular in a wall of the receiving space, preferably in the stirred vessel, in particular as a resistance heater in a floor of the receiving space, preferably in the floor of the Stirring vessel. In this case, the heating element can preferably be integrated flatly in the base or the stirred vessel base, so that as large an area as possible can be used for heating the medium (in particular in the stirred vessel). In particular, by means of an electrical current flow in the heating element, the heating element can be heated by the heating control.

Furthermore, it is conceivable that the temperature sensor is designed as an NTC sensor and is integrated in the receiving space, in particular in a wall of the receiving space, in particular in a stirred vessel. It can therefore be possible that the temperature sensor does not come into direct contact with the medium (in particular in the stirred vessel). This improves the service life of the temperature sensor and the safety when operating the domestic appliance, in particular the kitchen appliance.

A domestic appliance, in particular a kitchen appliance, is also protected, preferably for the (possibly at least partially automatic) preparation of at least one foodstuff, a system according to the invention being provided for the domestic appliance or the kitchen appliance. The domestic appliance according to the invention thus brings the same advantages as have been described in detail with reference to the system according to the invention.

1. a) Initiieren einer Aufheizphase mit einer derartigen Heizleistungsanpassung, dass eine (gemessene) Temperatur bei einem Aufnahmeraum des Hausgeräts, insbesondere einem Rührgefäß der Küchenmaschine, eine vorgegebene Soll-Temperatur anstrebt,
2. b) Initiieren einer Temperaturhaltungsphase, wenn die Temperatur die Soll-Temperatur erreicht hat, wobei in der Temperaturhaltungsphase eine Heizleistungsbegrenzung erfolgt,
3. c) Durchführen wenigstens einer Auswertung der Temperatur anhand der Soll-Temperatur während der Temperaturhaltungsphase, sodass ein Auswertungsergebnis bestimmt wird,
4. d) Initiieren einer Stabilisierungsphase, wenn das Auswertungsergebnis ein Stabilisierungskriterium erfüllt, wobei in der Stabilisierungsphase die Heizleistungsanpassung derart erfolgt, dass die Temperatur eine bestimmte Stabilisierungstemperatur anstrebt, wobei die Stabilisierungstemperatur größer ist als die Soll-Temperatur.

The invention also relates to a computer program product for adapting a heating power in a domestic appliance, in particular in a kitchen appliance. It is provided here that the computer program product is designed to carry out the following steps when executed by a processing device, in particular according to a method according to the invention:

1. a) initiating a heating phase with such a heating power adjustment that a (measured) temperature in a receiving space of the domestic appliance, in particular a mixing vessel of the kitchen appliance, strives for a predetermined target temperature,
2. b) initiation of a temperature maintenance phase when the temperature has reached the target temperature, with heating output being limited in the temperature maintenance phase,
3. c) Carrying out at least one evaluation of the temperature based on the target temperature during the temperature maintenance phase, so that an evaluation result is determined,
4. d) initiating a stabilization phase when the evaluation result fulfills a stabilization criterion, the heating output being adjusted in the stabilization phase in such a way that the temperature strives for a certain stabilization temperature, the stabilization temperature being greater than the target temperature.

Fig. 1

eine schematische Darstellung eines Hausgeräts,

Fig. 2

ein schematisches Blockdiagramm zur Visualisierung eines erfindungsgemäßen Verfahrens,

Fig. 3

eine schematische Messkurve zur Visualisierung eines erfindungsgemäßen Verfahrens.

The computer program product according to the invention thus has the same advantages as have been described in detail with reference to a method according to the invention.

Fig. 1

a schematic representation of a household appliance,

Fig. 2

a schematic block diagram for visualizing a method according to the invention,

Fig. 3

a schematic measurement curve for visualizing a method according to the invention.

In the following figures, the same reference numerals are used for the same technical features from different exemplary embodiments.

Figure 1 shows schematically a domestic appliance 10 according to the invention using the example of a kitchen appliance 10 with a system 200 according to the invention. It can be seen that a mixing vessel 20 is provided as a receiving space 20 for preparing food.

For this purpose, at least one food item can be accommodated in the stirred vessel 20. The medium 30 then present in the stirred vessel 20 is shown schematically with an exemplary fill level. At least one heating element 40 can be provided in the kitchen appliance 10 for heating the medium 30 and can be operated by a heating control as a function of a measured temperature T. For the heating control z. B. a control device 80 can be used, which controls an electrical energy transfer to the heating element 40 for heating as a function of temperature measured values. For improved visualization of the heating element 40, an area of a stirred vessel bottom 21 highlighted by a dashed line is shown enlarged. The heating element 40 can be integrated flatly in the stirred vessel bottom 21 in order to enable the medium 30 to be heated evenly. A temperature sensor 50 for measuring the actual temperature T and thus for recording the measured temperature values can also be integrated adjacent to the heating element 40 in the stirred vessel bottom 21.

During the heating control (e.g. depending on the medium 30 and / or the level of the medium 30 and / or the desired or set temperature) there may be a discrepancy between the measured actual temperature T and an actual temperature of the medium 30, For example, in relation to a location in the medium 30 further away from the heating element 40. Because the heating by the heating element 40 initially affects the area of the medium 30 immediately adjacent to the heating element 40, and then there is a more or less slow heat transfer to regions of the medium 30 that are further away. The heat transfer is promoted by the operation of a stirrer 25 in the stirred vessel 20, by means of which the medium 30 can be stirred for the preparation of the food contained therein.

In order to further promote the uniform and rapid heating of the entire medium 30, a method 100 according to the invention can be provided at least partially by evaluating a processing device 60, as will be described in more detail below.

Figure 2 shows schematically a sequence of a method 100 according to the invention. For example, the method 100 is initiated when a user of the domestic appliance 10 or the Food processor 10 wishes the food to be heated and accordingly sets a target temperature S for medium 30. In this case, a heating phase A is first carried out with a heating power adjustment of the heating element 40 such that the temperature T (actual temperature T) measured by the temperature sensor 50 strives for the predefined setpoint temperature S. The heating power adjustment is z. B. provided by an electrical energy transfer to the heating element 40, for example. By a control device 80, wherein the electrical power transferred to the heating element 40 is adapted as a function of the temperature T. If, at this point in time, there is a medium 30 in the receiving space 20, in particular in the stirred vessel 20, which is in indirect contact with the heating element 40 via the base 21, in particular the stirred vessel base 21, heat can be transferred from the heating element 40 to the medium 30. For this purpose, the bottom 21 can be formed at least partially from a thermally conductive material, such as, for example, a metal. It is clear that there is a discrepancy between the actual temperature of the medium 30 and the measured actual temperature T, since the heating of the medium 30 usually takes time. Therefore, further steps are carried out in order to reduce this period of time as much as possible, and thus to enable an improved preparation of the food in the medium.

In the following step 100.1 it can therefore be checked whether the measured actual temperature T has reached the setpoint temperature S. If this is not the case, heating phase A continues. If this is the case, a temperature maintenance phase B is carried out, with heating output being limited in temperature maintenance phase B. In other words, heating takes place here with limited power (for example, at most up to the maximum holding heating power), so that a period of time for homogenizing the temperature in the medium is provided. The maximum holding heating power can be determined as a function of a maximum heating power.

During the temperature maintenance phase B, the temperature T can still be measured. A minimum can also be formed from several measured temperature values (i.e. the smallest temperature value can be determined).

In the further step 100.2 it is preferably checked whether a difference between the minimum (that is to say the smallest measured temperature T) and the setpoint temperature S is still below a threshold value. In other words, the following test is carried out: $$\min \left(\mathrm{Tbowl}\right)-\mathrm{Ttarget}<\mathrm{Threshold}\_\mathrm{stb}.$$

Here, Tbowl is the measured temperature T, min is the minimum, Ttarget is the specified target temperature S and Threshold_stb is the predefined threshold value. In this way, the temperature T is evaluated on the basis of the setpoint temperature S during the temperature maintenance phase B, so that an evaluation result is determined. If the result of this test (i.e. the comparison) is positive (the difference or the amount of the difference is below the threshold value), i.e. the evaluation result does not meet a stabilization criterion, temperature maintenance phase B continues to be carried out. Otherwise the stabilization criterion is present and a stabilization phase C is carried out.

In the stabilization phase C, the heating output is adapted in particular in such a way that the temperature T strives for a certain stabilization temperature ST, the stabilization temperature ST being greater than the target temperature S. In other words, an intentional overriding of the target temperature S is carried out in the stabilization phase C. to enable improved heating of the medium.

mit Threshold_aufh als der weitere Schwellenwert, welcher ggf. von der Stabilisierungstemperatur ST abhängig ist. Falls diese Prüfung positiv ist, also der Schwellenwert überschritten wird, wechselt die Heizleistungsanpassung zur Aufheizphase A. Andernfalls (oder alternativ) kann eine weitere Prüfung gemäß Schritt 100.4 durchgeführt werden: $$\mathrm{Tbowl}>\mathrm{Ttarget},\mathrm{new}\mathrm{OR}\mathrm{TIMER}>\mathrm{Time}\_\mathrm{check},$$

In a further step 100.3 it can then optionally be checked whether a minimum of the measured temperature T subtracted by the setpoint temperature S is above a further threshold value. In other words, the following test is carried out: $$\min \left(\mathrm{Tbowl}\right)-\mathrm{Ttarget}>\mathrm{Threshold}\_\mathrm{stop},$$

with Threshold_aufh as the further threshold value, which may be dependent on the stabilization temperature ST. If this test is positive, i.e. the threshold value is exceeded, the heating output adjustment changes to heating phase A. Otherwise (or alternatively) a further test according to step 100.4 can be carried out: $$\mathrm{Tbowl}>\mathrm{Ttarget},\mathrm{new}\mathrm{OR}\mathrm{TIMER}>\mathrm{Time}\_\mathrm{check},$$

TIMER is the output of a timer and indicates the duration of the implementation of the stabilization phase C. Time_check is a time threshold value. If the duration of the stabilization phase C exceeds a maximum value, or if the measured temperature T exceeds a “new” target temperature Ttarget, new, the result of this test is positive. In this case, there is another change to temperature maintenance phase B. Otherwise, the stabilization phase C continues to be carried out. The new target temperature Ttarget, new is in particular the stabilization temperature ST.

wobei dTbowl, longterm ein langfristiges Steigungsmaß (langfristige Steigung) für die gemessene Temperatur T ist. Dieses kann bspw. anhand eines Verlaufs von gemessenen Temperaturmesswerten der gemesseneren Temperatur T ermittelt werden, z. B. durch eine Differenzbildung der Messwerte und/oder durch eine Interpolation oder dergleichen.The values Time_check and Ttarget, new are calculated in stabilization phase C if necessary. Time_check can be calculated, for example, by: $$\mathrm{Time}\_\mathrm{check}=\left(\mathrm{Ttarget}-\min \left(\mathrm{Tbowl}\right)\right)/\mathrm{dTbowl},\mathrm{longterm},$$

where dTbowl, longterm is a long-term slope measure (long-term slope) for the measured temperature T. This can be determined, for example, on the basis of a curve of measured temperature measurement values of the measured temperature T, e.g. B. by forming the difference between the measured values and / or by interpolation or the like.

Then, if necessary, Time_check can be compared with a specified maximum value for Time_check, and if it is exceeded, the maximum value can be set for Time_check.

Furthermore, it can be provided that the stabilization temperature ST is an offset greater than the target temperature S, the offset being determined by the difference between the target temperature S and at least one temperature value determined in the temperature maintenance phase B, in particular a minimum of these temperature values, is determined. To determine the stabilization temperature ST, for example, the value “Time_check”, that is to say the predefined maximum duration of the stabilization phase C, can first be multiplied by dTbowl, longterm. This value can then be compared with the specified target temperature S (or Ttarget) must be added. If necessary, this sum can be limited to a maximum value and then forms the stabilization temperature ST (Ttarget, new).

In Figure 3 a sequence of a method 100 according to the invention is schematically visualized on the basis of exemplary measured values over time t. A curve of measured values for a temperature T measured by the temperature sensor 50 is shown and compared with a course of an actual temperature of a medium 30 (medium temperature M) (which may not be directly measurable under practical conditions). An external sensor, for example, can be used to detect the medium temperature M. From the measured values for the measured temperature T, z. B. a long-term slope L can be calculated, which can then correspond to the value dTbowl, longterm. The long-term slope L is, for example, the slope of the curve shown for the measured temperature T over a period of 0.5 s to 200 s, preferably 1 s to 100 s, preferably 60 s .

First, a heating phase A for heating the medium 30 is carried out. In this, a predefined setpoint temperature S can be used for heating control, the control variable used for this preferably being the temperature T measured by the temperature sensor 50, and thus a temperature value for the temperature T forms the actual value, which is used with the setpoint temperature S as current target temperature AS can be compared. First of all, the temperature T strives to reach the target temperature S in the heating phase A. When the target temperature S is reached by the temperature T, the medium temperature M can still be below the target temperature S, as shown on the basis Figure 3 is recognizable. In order to reduce this difference as quickly as possible, further phases can be carried out. First of all, this can be the temperature maintenance phase B, during which heating output is limited. A minimum of the temperature value minT can be determined in this phase, e.g. B. a minimum of all temperature values measured in this phase in order to determine an evaluation result by comparison with a threshold value. Depending on the evaluation result, a stabilization phase C can then be carried out if the evaluation result fulfills a stabilization criterion, with the heating output being adjusted in stabilization phase C in such a way that the temperature T reaches a certain level Aiming at stabilization temperature ST, the stabilization temperature ST being greater than the target temperature S.

Correspondingly, the current setpoint temperature AS used for heating control can initially correspond to the predefined setpoint temperature S in the heating phase A and to the stabilization temperature ST in the stabilization phase C. To form the stabilization temperature ST, the predefined setpoint temperature S can be increased by an offset O, if necessary. It is also shown that the stabilization phases C can also have a different duration (stabilization duration or stabilization duration) DT1 and DT2. A first stabilization phase C ends because the stabilization temperature ST is reached, and the second stabilization phase C ends because the duration DT2 exceeds a maximum duration.

The above explanation of the embodiments describes the present invention exclusively in the context of examples.

List of reference symbols

10

Food processor

20th

Receiving space, mixing vessel

21

Bottom, stirred vessel bottom

25th

Agitator

30th

medium

40

Heating element

50

Temperature sensor

60

Processing device

80

Control device

100

Procedure

200

system

minT

Minimum temperature value

A.

Heating phase

AS

current target temperature

B.

Temperature maintenance phase

C.

Stabilization phase

L.

Long term slope

M.

Medium temperature

O

Offset

S.

specified target temperature

ST

Stabilization temperature

T

Temperature, actual temperature

DT1

first stabilization period

DT2

second stabilization period

Claims (15)

1. Method (100) for adapting a heating power of at least one heating element (40) of a domestic appliance (10), in particular a food processor (10) for at least partially automatic preparation of food, wherein the domestic appliance (10) comprises a temperature sensor (50) for measuring a temperature (T) at a receiving space (20) of the domestic appliance (10),
   wherein the following steps are provided:

   a) performing a heating phase (A) with such a heating power adjustment that the temperature (T) aims at a predetermined set temperature (S),

   b) performing a temperature holding phase (B) when the temperature (T) has reached the set temperature (S), wherein heating power limitation occurs in the temperature holding phase (B),

   c) performing at least one evaluation of the temperature (T) based on the set temperature (S) during the temperature holding phase (B) so that an evaluation result is determined,

   d) performing a stabilization phase (C) when the evaluation result satisfies a stabilization criterion, wherein in the stabilization phase (C) the heating power adjustment occurs in such a way that the temperature (T) aims at a certain stabilization temperature (ST), wherein the stabilization temperature (ST) is greater than the set temperature (S).
2. Method (100) according to claim 1,
   characterized in that
   the stabilization temperature (ST) is determined on the basis of the evaluation result, wherein preferably the stabilization temperature (ST) is limited by a maximum offset.
3. Method (100) according to claim 1 or 2,
   characterized in that
   the heating power is adjusted for heating power limitation in such a way that the heating power is limited to a predetermined maximum holding heating power, wherein in the heating phase (A) and/or the stabilization phase (C) the heating power adjustment, in particular as a heating power control, occurs in such a way that the heating power limitation is cancelled, or in the stabilization phase (C) the heating power adjustment occurs in such a way that the heating power limitation is limited to a higher value than in the temperature holding phase (B).
4. Method (100) according to any one of the preceding claims,
   characterized in that
   in the case of the heating power limitation for the temperature holding phase (B), the heating power is limited to a predetermined maximum holding heating power in the range from 10% to 90%, preferably 20% to 70%, preferably 30% to 60%, particularly preferably 40% to 50%, in particular 40%, of a maximum heating power and/or in the temperature holding phase (B), one or more temperature values are determined by at least one measurement of the temperature (T) for the purpose of temperature monitoring, wherein in step c) the evaluation is carried out by determining a difference between the determined temperature value or one of the determined temperature values, in particular a minimum of the temperature values, and the set temperature (S), wherein preferably the difference forms the evaluation result.
5. Method (100) according to any one of the preceding claims,
   characterized in that
   during the stabilization phase (C) a temporal stabilization duration of the performance of the stabilization phase (C) is determined, wherein the subsequent step is provided after step d):

   - performing a change from the stabilization phase (C) to the temperature holding phase (B) if the determined temporal stabilization duration exceeds a certain stabilization time specification.
6. Method (100) according to any one of the preceding claims,
   characterized in that
   during the stabilization phase (C) for temperature monitoring at least one temperature value is determined by at least one measurement of the temperature (T), wherein the subsequent step is provided after step d):

   - performing a change from the stabilization phase (C) to the temperature holding phase (B) if, during the stabilization phase (C), an evaluation of the temperature value on the basis of the stabilization temperature (ST) satisfies a termination criterion, in particular if it is indicated by the temperature value that the temperature (T) has reached the stabilization temperature (ST).
7. Method (100) according to any one of the preceding claims,
   characterized in that
   during the heating phase (A) for temperature monitoring, a plurality of temperature values are determined by measurements of the temperature (T), so that a temperature rise is determined, wherein a ratio of the evaluation result determined in accordance with step c) to the determined temperature rise is determined in order to determine the stabilization time specification, wherein preferably the stabilization time specification is limited by a maximum duration which is preferably in the range from 100 s to 1000 s, preferably 200 s to 800 s.
8. Method (100) according to any one of the preceding claims,
   characterized in that
   during the stabilization phase (C) for temperature monitoring at least one temperature value is determined by at least one measurement of the temperature (T), wherein the subsequent step is provided after step d):

   - performing a change from the stabilization phase (C) to the heating phase (A) if, during the stabilization phase (C), an evaluation of the temperature value satisfies a heating criterion, in particular if a temperature difference between the temperature value and the set temperature (S) exceeds a predetermined threshold value.
9. Method (100) according to any one of the preceding claims,
   characterized in that
   during the heating phase (A) and/or during the temperature holding phase (B) and/or during the stabilization phase (C), temperature monitoring is carried out in that a plurality of measurements of the temperature (T) are carried out successively in time, preferably at regular intervals, by the temperature sensor (50) in order to determine at least one temperature value in each case, in order to carry out the evaluation according to step c) in particular on the basis of the temperature value and/or in order to determine when the temperature (T) has reached the set temperature (S) and/or the stabilization temperature (ST).
10. Method (100) according to any one of the preceding claims,
    characterized in that
    the heating phase (A) and/or the temperature holding phase (B) and/or the stabilization phase (C) is carried out during a preparation of food in order to heat the food in the receiving space (20) to the set temperature (S), wherein the measured temperature (T) is specific for the temperature of the food and deviating from the latter, wherein the stabilization temperature (ST) and/or a stabilization time duration (DT) is determined in such a way that in the stabilization phase (C) an approximation of the temperature of the food to the set temperature (S) occurs at a higher speed than in the temperature holding phase (B).
11. Method (100) according to any one of the preceding claims,
    characterized in that
    the stabilization criterion is fulfilled when the evaluation result, preferably a difference between a determined temperature value or one of the determined temperature values, in particular a minimum of the temperature values, and the set temperature (S), exceeds a predefined threshold value, wherein preferably the threshold value is defined independently of food, and preferably the threshold value is in the range from 1 K to 10 K, preferably 2 K to 9 K, preferably 3 K to 8 K, particularly preferably 3.8 K to 7 K, and/or the stabilization temperature (ST) is greater than the set temperature (S) by an offset, wherein the offset is determined by the difference between the set temperature (S) and at least one temperature value determined in the temperature holding phase (B), in particular a minimum of these temperature values, and in particular may correspond at most to a maximum offset in the range from 8 K to 20 K, preferably 10 K to 15 K, preferably 12 K to 14 K.
12. System (200) for adjusting a heating power in a domestic appliance (10), in particular in a food processor (10), comprising:

    - at least one temperature sensor (50) for performing at least one measurement of a temperature (T) at a receiving space (20) of the domestic appliance (10), in particular at a mixing vessel (20) of the food processor (10),

    - at least one control device (80) for controlling at least one heating element (40) of the domestic appliance (10) depending on a heating power adjustment, so that in a heating phase (A) the temperature (T) aims at a predetermined set temperature (S), and in a temperature holding phase (B) a heating power limitation occurs,

    - at least one processing device (60) for evaluating the temperature (T) on the basis of the set temperature (S) at least in the temperature holding phase (B),
    wherein the processing device (60) is adapted to initiate a stabilization phase (C) depending on the evaluation, wherein in the stabilization phase (C) the heating power adjustment is performable such that the temperature (T) aims at a certain stabilization temperature (ST), wherein the stabilization temperature (ST) is greater than the set temperature (S).
13. System (200) according to the preceding claim,
    characterized in that
    the heating element (40) is integrated with the receiving space (20), in particular as a resistance heater in a floor of the receiving space (20), and/or the temperature sensor (50) is designed as an NTC sensor and is integrated with the receiving space (20), and/or the system (200) can be operated according to a method (100) according to one of the preceding claims.
14. Domestic appliance (10) for preparing at least one food,
    characterized in that
    a system (200) according to any one of claims 12 or 13 is provided.
15. Computer program product for adjusting a heating power in a domestic appliance (10), wherein the computer program product is adapted to perform the following steps when executed by a processing device (60) according to a method (100) according to any of claims 1-11:

    a) initiating a heating phase (A) with a heating power adjustment such that a temperature (T) at a receiving space (20) of the domestic appliance (10) aims at a predetermined set temperature (S),

    b) initiating a temperature holding phase (B) when the temperature (T) has reached the set temperature (S), wherein heating power limitation occurs in the temperature holding phase (B),

    c) performing at least one evaluation of the temperature (T) based on the set temperature (S) during the temperature holding phase (B) so that an evaluation result is determined,

    d) initiating a stabilization phase (C) when the evaluation result satisfies a stabilization criterion, wherein in the stabilization phase (C) the heating power adjustment occurs in such a way that the temperature (T) aims at a certain stabilization temperature (ST), wherein the stabilization temperature (ST) is greater than the set temperature (S).

Images